MT. OSO
(13,684')July 30, 2009
By Tim Briese
Backpack in, July 29: 5.8 miles, 700' elevation gain, 2:40 time
Climb, July 30: 13.8 miles, 4400' elevation gain, 11:10 roundtrip time
Backpack out, July 31: 5.8 miles, 2200' elevation gain, 3:50 time
Total: 25.4 miles, 7300' elevation gain
Mt. Oso is perhaps the most remote of any of Colorado=s highest 200 peaks. For this reason it was a major prize that Brian and I sought during the 2009 summer climbing season. Our plan was to backpack from the Beartown Trailhead over Hunchback Pass in the afternoon after our climb of White Dome and Peak One in the morning. We would backpack down the Vallecito drainage and camp at the junction of Vallecito and Rock Creeks to be in position for a long dayhike of Mt. Oso via Rock Lake the next morning.
After our climb of White Dome and Peak One we returned to my truck parked at Kite Lake early in the afternoon. The weather had turned stormy and neither of us cared to set forth on the exposed hike over the pass during a lightning storm. We drove a half mile down the road from the lake to the Beartown Trailhead and readied our backpacks and waited a couple of hours while pondering what to do. Finally we got a break in the weather and decided to take off about 3:30. We packed briskly up the trail on the 700 foot climb to the 12,500 foot pass in only 40 minutes. Then we began the long descent down the Vallecito drainage on the other side. We made good time considering we were carrying full packs and arrived at the junction of the Vallecito and Rock Creek trails around 6:10. Another thunderstorm was moving in so we quickly found a camping spot in the woods nearby and threw up the tent. A downpour unleashed just as we jumped inside.
We rose early the next morning and headed up the Rock Creek Trail at 3:30 a.m. It was wet and chilly but a starry sky bolstered our spirits. In the upper part of the drainage numerous patches of wet and sometimes frost-covered willows hung over the trail and drenched my pants as I walked by, which was very cold. Ice formed on my trekking poles and glistened in the light of my headlamp. I ruefully wished I had put on my rain pants before I got so cold. We reached Rock Lake at dawn, at about 5:50, after hiking four and a half miles from camp in the dark. I shivered with cold as I filtered water from the lake. There were two tents and some llamas in the willows a short distance away.
We found a well-cairned trail on the east side of the scenic lake that neatly switchbacked 600 feet up to the crest of a rugged headwall south of the lake. Once we gained the crest of the 12,400 foot ridge we followed the trail west a short distance along the top of the ridge. When the trail turned to the south and began to descend we left the trail and bushwhacked to the southwest over a gentle 12,650 foot ridge. At this point we finally gained a view of Mt. Oso and the rest of the circuitous route to its summit. We dropped about 400 feet to the southwest on grassy slopes into a broad basin northwest of Moon Lake and contoured toward Oso=s southeast ridge, trying to lose as little elevation as possible. We aimed for a steep gully that appeared to be the only reasonable route up through cliff bands to gain the ridge. After crossing a rough talus slope and climbing a steep grassy slope we reached the base of the gully at 8:15. In short order we climbed the steep gully on mostly solid grassy footing and topped out on the ridge at about 13,000 feet. The rough ridge was quite steep and loose for a while but at 13,400 feet the terrain mellowed considerably and all that remained was a pleasant hike across a solid talus slope to the summit.
We stepped on top at 9:40, more than six vigorous hours after we had left camp. It felt great to be there! Not only is Mt. Oso a very remote peak, but the route to its summit is more complicated and involved than that of most Colorado peaks. It didn=t help that I felt rather ill from dehydration this morning, something that rarely happens to me. Summit exhilaration can cure a lot of things, though! We sat on top for about 35 minutes, basking in the glow of the accomplishment and admiring the great views all around. The Chicago Basin peaks punctuated the horizon to the west and the Grenadiers did likewise to the northwest. Rock Lake lay far below to the east. Moon Lake graced the basin to the southeast. Far away to the south lay the Vallecito Reservoir, and the closest 2WD trailhead to this peak, from which Garratt and Martin propose that it be climbed. We marveled at what a lengthy hike it would take to get to this summit from there!
Realizing we had a long haul back to camp we left the summit at 10:15 and began our descent. We made our way back down the ridge to the top of the gully and gazed across the basin at the 400 foot reclimb that awaited us on the other side. We hoped the weather would hold out until we got back down to Rock Lake, for it was looking threatening already. Thunder rumbled and showers passed by but we made it to the lake in relatively dry condition at about 12:30. After a water and food break we headed back down the Rock Creek Trail as another shower moved in. We trudged down the scenic valley and arrived back at camp at 2:45.
The sun came out and we briefly pondered packing back out to the Beartown Trailhead that evening, but a couple of hours later another heavy thunderstorm moved in and we were glad we didn=t. We also considered the possibility of climbing the Guardian and Mt. Silex the next morning, a tempting proposition since we were literally camped in the shadow of the Guardian. However, my arthritic knee had had about enough, or would at any rate considerably slow down my climbing on steeper terrain. Also, that climb would have required that we wait for daylight to start. The weather pattern didn=t bode well for success given these parameters so we decided to forgo that option and save those peaks for next year.
The next morning we packed up and left our campsite at 7:10. We made the long grind back up to Hunchback Pass as showers began to roll in. We made it back to the truck around eleven o=clock. Rain pelted down for much of the way on the long, slow drive back to Brian=s car. Afterward we headed for Lake City, eager for a shower and dinner.
